Chalcogen substitution: Effect of oxygen-by-sulfur exchange on structural and spectroscopic properties of flavonols

Falantin, Cécilia; Moncomble, Aurélien; Person, A. Le; Cornard, Jean-Paul

doi:10.1016/j.saa.2017.06.022

Cited by 8 publications

(5 citation statements)

References 67 publications

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“…[1,2] As ac onsequence,t he effect of substitution of oxygen by sulfur on many properties is of particular relevance in biochemistry [3] and chemical reactivity. [4] Therefore,t he investigation of the changes occurring in structural, [5] chemical-physical [6] and spectroscopic properties [7] upon such substitution is of much general interest.…”

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confidence: 99%

Unveiling the Sulfur–Sulfur Bridge: Accurate Structural and Energetic Characterization of a Homochalcogen Intermolecular Bond

et al. 2018

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By combining rotational spectroscopyinsupersonic expansion with the capability of state-of-the-art quantumchemical computations in accurately determining structural and energetic properties,the genuine nature of as ulfur-sulfur chalcogen bond between dimethyl sulfide and sulfur dioxide has been unveiled in agas-jet environment free from collision, solvent and matrix perturbations.ASAPT analysis pointed out that electrostatic S···S interactions play the dominant role in determining the stability of the complex, largely overcoming dispersion and CÀH···O hydrogen-bond contributions.Indeed, in agreement with the analysis of the quadrupole-coupling constants and of the methyl internal rotation barrier,the NBO and NOCV/CD approaches show am arked charge transfer between the sulfur atoms.B ased on the assignment of the rotational spectra for 7i sotopologues,a na ccurate semiexperimental equilibrium structure for the heavy-atom backbone of the molecular complex has been determined, whichis characterized by aS ···S distance (2.947(3) )w ell belowt he sum of van der Waals radii.

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confidence: 99%

Unveiling the Sulfur–Sulfur Bridge: Accurate Structural and Energetic Characterization of a Homochalcogen Intermolecular Bond

et al. 2018

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“…Given this negligible difference, only 180 ° torsion starting with the most stable conformations was considered in the following discussion. Falantin et al (2017) also found 3OH with C s symmetry with the strong intramolecular H-bond Fig. 1.…”

Section: Resultsmentioning

confidence: 89%

Influence of catecholic ring torsion on hydroxyflavones

Michalík

Biela

Cagardová

et al. 2020

Acta Chimica Slovaca

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Systematic quantum chemical investigation of quercetin and selected eight mono- and bihydroxyflavonols is presented. Structural analysis based on the Density Functional Theory showed that the energetically preferred conformation of flavonols substituted at the C5 and C3 atoms by a hydroxyl group is stabilised via intramolecular hydrogen bonds occurring between the (C4)O···HO(3 or 5) atomic pairs. Depending on the hydroxyl group positions, energetically preferred torsional orientation of the phenyl ring with respect to the planar benzo-γ-pyrone moiety changed from 0 to 180 degrees. Gas-phase electron transitions were investigated using the time-dependent DFT treatment. The dependence of maximal wavelengths on the torsional deformation of the phenyl ring is of a similar shape, i.e. minima observed for the perpendicular orientation and maxima for the planar one. Shape and energies of the Highest Occupied (HOMO) and Lowest Unoccupied (LUMO) Molecular Orbitals were compared. The obtained theoretical results were compared with available experimental data.

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“…As reported before, 51 these derivatives showed emission from the normal state in methanol. 3-Hydroxyflavothione derivatives ( 13A – 18A ) are either not emissive or show a very low emission 63 ( Figure S128 ) due to more efficient intersystem crossing related to the heavy atom effect of the sulfur atom. 64 The observed Stokes shifts were always below 100 nm in polar methanol; thus, the emission was ascribed to the normal form emission, as also demonstrated by Chou and co-workers for 3A .…”

Section: Resultsmentioning

confidence: 99%

Structure–Photoreactivity Relationship Study of Substituted 3-Hydroxyflavones and 3-Hydroxyflavothiones for Improving Carbon Monoxide Photorelease

Jézéquel,

Svěrák,

Ramundo

et al. 2024

J. Org. Chem.

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Carbon monoxide (CO) is notorious for its toxic effects but is also recognized as a gasotransmitter with considerable therapeutic potential. Due to the inherent challenges in its delivery, the utilization of organic CO photoreleasing molecules (photo-CORMs) represents an interesting alternative to CO administration characterized by high spatial and temporal precision of release. This paper focused on the design, synthesis, and photophysical and photochemical studies of 20 3-hydroxyflavone (flavonol) and 3hydroxyflavothione derivatives as photoCORMs. Newly synthesized compounds bearing various electron-donating and electron-withdrawing groups show bathochromically shifted absorption maxima and considerably enhanced CO release yields compared to the parent unsubstituted flavonol, exceeding 0.8 equiv of released CO in derivatives exhibiting excited states with a charge-transfer character. Until now, such outcomes have been limited to flavonol derivatives possessing a π-extended aromatic system. In addition, thione analogs of flavonols, 3-hydroxyflavothiones, show substantial bathochromic shifts of their absorption maxima and enhanced photosensitivity but provide lower yields of CO formation. Our study elucidates in detail the mechanism of CO photorelease from flavonols and flavothiones, utilizing steady-state and timeresolved spectroscopies and photoproduct analyses, with a particular emphasis on unraveling the structure−photoreactivity relationship and understanding competing side processes.

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Chalcogen substitution: Effect of oxygen-by-sulfur exchange on structural and spectroscopic properties of flavonols

Cited by 8 publications

References 67 publications

Unveiling the Sulfur–Sulfur Bridge: Accurate Structural and Energetic Characterization of a Homochalcogen Intermolecular Bond

Unveiling the Sulfur–Sulfur Bridge: Accurate Structural and Energetic Characterization of a Homochalcogen Intermolecular Bond

Influence of catecholic ring torsion on hydroxyflavones

Structure–Photoreactivity Relationship Study of Substituted 3-Hydroxyflavones and 3-Hydroxyflavothiones for Improving Carbon Monoxide Photorelease

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